Remote Sensing Systems (RSS) SMAP Sea Surface Salinity (SSS) V4.0 Datasets Release
Thursday, August 29, 2019
The PO.DAAC is pleased to announce the release of the version 4.0 SMAP Sea Surface Salinity (SSS) data from Remote Sensing Systems (RSS). Enhancements over the previous release include:
- Improved land correction allows for salinity retrievals within 30 – 40km of the coast. The land correction uses a land correction table at 0.125 degree spatial resolution. The land emission that is used in the land correction is based on SMAP TB.
- Replacement of the previous NCEP sea-ice mask with one based on RSS AMSR-2 and implementation of a sea-ice threshold of 0.3% (gain weighted sea-ice fraction).
- Revised solar flagging that depends on glint angle and wind speed.
- Inclusion of estimated SSS-uncertainty in the L3 products.
Datasets comprising this release include Level 2C and L3 mapped monthly and 8-day running mean SMAP-SSS. All products are in the netCDF4 file format and are CF/ACDD metadata standards compliant. Note that unlike in prior releases, the 40-km and 70-km fields have been consolidated as variables within a single data product rather than being made available as distinct datasets. The 70-km data are based on a smoothing of the 40-km product, which is retrieved directly from the geophysical model function (Meissner et al. 2018). The 70-km version should be considered the official product with the 40-km included for experimental purposes. For most open ocean applications, the 70-km fields are the best used since they have significantly lower noise than the 40-km data. We also recommend the use of the V4.0 forward stream data over the prior version, which is deprecated and will be retired within the next 6 months.
The RSS SMAP-SSS V4.0 datasets are described, discoverable, and accessible via the PO.DAAC data portal, as are the associated technical documentation. General information regarding the SMAP mission is available from the mission website and also via PO.DAAC’s SMAP and salinity webpages.
Reference: Meissner, T., F.J. Wentz, and D.M. Le Vine, 2019, The Salinity Retrieval Algorithms for the NASA Aquarius Version 5 and SMAP Version 3 Releases, Remote Sensing 10, 1121, doi:10.3390/rs10071121.
Citation: Meissner, T., F. J. Wentz, A. Manaster, R. Lindsley, 2019: Remote Sensing Systems SMAP Ocean Surface Salinities [Level 2C, Level 3 Running 8-day, Level 3 Monthly], Version 4.0 validated release. Remote Sensing Systems, Santa Rosa, CA, USA. Available online at www.remss.com/missions/smap, doi: 10.5067/SMP40-2SOCS,10.5067/SMP40-3SPCS, 10.5067/SMP40-3SMCS
JPL SMAP Sea Surface Salinity (SSS) CAP V4.2 Dataset released
The PO.DAAC is pleased to announce the availability of the PI-produced JPL V4.2 SMAP Sea Surface Salinity (SSS) and extreme winds data, which includes Level-2B (L2B) and Level 3 (L3) standard datasets based on the JPL Combined Active-Passive (CAP) algorithm applied to data from the NASA Soil Moisture Active Passive (SMAP) observatory. Included as part of this release is also a near real-time L2B dataset, available with a latency of about 4.3 hours as a 8-day rolling store. For science applications, use of the standard products is strongly advised. We also recommend the use of the V4.2 forward stream data over the prior version, which is deprecated and will be retired within the next 6 months.
SMAP SSS V4.2 accommodates changes in the underlying Level 1B-TB data resulting from the SMAP mission data reprocessing in June 2018. Updates with version 4.2 include: improvement in the brightness temperature (TB) calibration using an adjusted reflector emissivity, inclusion of a Sea Surface Temperature (SST) dependent flat surface emissivity model, use of updated land correction tables, and inclusion of averaged ice concentration ancillary data in the V4.2 datasets. Data begins on 1 April 2015 and is ongoing. Data sets comprising this release include the L2B orbital data and two L3 mapped, global coverage salinity datasets: an 8-day running mean dataset based on the repeat orbit of the SMAP mission, along with a monthly average dataset. The L2B data are provided on a 25 km swath grid while the L3 data are gridded at 0.25o x 0.25o. The spatial resolution of all four datasets is approximately 60 km. The L2B dataset is in HDF5 format, and the L3 datasets are in netCDF4 file format. All datasets are CF/ACDD metadata standards compliant, and include estimated SSS uncertainty fields.
See all Official NASA SMAP Mission News
See all PO.DAAC Announcements